Telephone-exchange system.



F. V- YOUNG.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB- IT, I917- Patented Den 4, 11917.

i amt" is.

EEEEEIcK v. Yoinve, or NEWARK, NEW JERSEY, ASSIGNOR rowEsrEnn ELECTRICCOMPANY, mCoEroEA'rEi), E -1\ Ew YORK,.1\T.Y., A CORPORATION on NEWYORK.

To all whom it may concern:

' Be it known that I, FREDERICK VrYoUNc,

a citizen of the United States, residing at Newark, in the countyofEsseX and State of New Jersey, have invented certain new and useiulImprovements in Telephone-EX- change Systems, of which the following isa full, clear, concise, and exact description.

This invention relates to telephone eX- change systems, and moreparticularly to such systems of the central energy type. I The objectofthis invention is theproduction of improved signaling means forsuchscribers lines A and B, terminating at a central'oiiice, and a cordcircuit C'thereat for connecting thesubscribers lines. It will beunderstood that a plurality oflines, similar to A andB, terminate at thecentral office, but,for thesake of simplicity, only thetwo'lines areshown. It is'believed that the inventionl. will be fully understood froma'description of the operation of the system shown inthedrawing,

and it willbe sodescribed.

Assuming that subscriber A desires to be connected to subscriber B, A.will signal the central oflice in the usual manner, whereupon theoperator Wlll' insert the answering plug of cord circuit G into the jackassooiated with line A. The normal contacts of the jack will be therebyopened, causing the release of line relay 5 to retire the line signal.The supervisory relay 6 also operates, and if the listening key 7 hasnot been actuated, answering supervisory lamp 8 will be intermittentlyoperated to furnish a signal to the operator. The operating circuit forthe answering supervisory lamp 8 may be traced from battery throughinterrupter 9, lower normal contact of relay 10, lefthand normal contactof relay 11, alternate T Specification of Letters Patent.

T 'EEHoNE- X I-IANGE SYSTEM.

rammed et. a, ie 'r.

. Application fil ed February 17, 1917. Serial No. 149,214.

contact of relay 6, lamp 8, and sleeve contacts of the answeringplug andjack to ground. Upon the operation oft-the listen ing key, the operatorstelephone set is connected to the tip and ring strands of the cordcircuit, and relays 1-0 hnd 11 are oper ated over a circuit from batterythrough the right-hand winding of relay 11, lower winding of-relay10,and contact 12 of listening key 7 to ground. The operation of theserelays opens the circuit including the in terrupter 9 and lamp 8,whereupon the lamp willcease to flash. Upon the operation of relay 11, alocking circuit established therefor from battery through the left-handwinding of relay 11, left hancl alternate contact thereof, alternatecontact of relay 6, lamp 8, and sleeve contacts of the answerin plug andjack to ground. The left-hand winding of relay 11 is of high resistanceso that when connected in series with the lamp 8, this lamp will notreceive suilicient current to permit it to lure nish a signal; 1

After conversing with the calling sub scriber' and upon being advisedthat suba scriber A desires to be connected with the line of subscriberB, the operator restores the listening key to normal position andinserts the calling plug of the cord circuit G into the jack of line B.Upon the restora tion of listening key 7 to normal position, relay 10releases, and upon the insertion of the calling plug into the jack oftheline B, calling supervisory lamp 19 is lighted. The operator may nowsignal subscriber B by actuating the usual ringing key .13. SubscriberB, in responding, causes the. operation of supervisory relay 16,whereupon the lamp 19 is extinguished The closure of the alternatecontact of relay 16, upon the operation thereof, does not include theinterrupter 9 in circuit with the calling supervisory lamp 19, for thereason that relay 11 is now locked up and its right-hand contact isopen. The subscribers, upon finishing a conversation, restore thereceivers to the switchhooks, whereupon supervisory relays 6 and 16release. The release of relay 6 opens a locking circuit for relay 11,permitting this relay to release. The release of these two supervisoryrelays also completes an operating circuit for each supervisory lamp,whereupon these lamps glow to furnish disconnect signals. The operatormay then Withdraw the plugs from the jacks, whereupon all apparatusreturns to normal.

Suppose, however, that before the plugs were withdrawn from the jacks,subscriber A should desire to make a recall. Then the removal of thereceiver from the switchhook by subscriber A causes the intermittentoperation of the answering supervisory lamp phone set to the cordcircuit. The actuation of the listening key causes the operation ofrelays 10 and 11, and a locking circuit Will thereby be completed forone or both of these relays, depending upon whether one or bothsupervisory relays are operated. Supervisory relay 6 controls thelocking circuit of. relay 11, and supervisory relay 16 controls thelocking circuit of relay 10. The upper Winding of relay 10 is of highresistance so that when connected in circuit with lamp 19, the lamp willnot receive sufficient current to permit it to furnish a signal. Theoperator, after conversing with the subscriber who has made therecall,may remove the plug of the cord circuit connected with the other line,and complete connection with the line desired by the subscriberrecalling. In this connection, it may be noted that each end of the cordcircuit is similarly equipped so that either end may be employed as ananswering end and either end as a calling end. i

What is claimed is: v

' 1. A telephone exchange syste m'comprise ing telephone lines, alinkcircuit for inter connecting the lines, a supervisory relay, a.

signaling device, a listening key, a second relay energized upon theactuation of the listening key, a locking circuit therefor including thesignaling device and contacts of the supervisory relay, and interruptermechanism brought into circuit with the signaling device by thesubsequent denergization of the second relay followed by theenergization of the supervisory relay.

2. A telephone exchange system comprising telephone lines, a linkcircuit for interconnecting the lines, a supervisory relay for each endof the link circuit, a signaling device controlled by each supervisoryrelay, a listening key, a second and a third relay energized by theactuation of the listening key, a locking circuit for the second relayincluding contacts of one supervisory relay and one signaling device,interrupter mechanism, and a circuit for the signaling device and theinterrupter mechanism including contacts of one supervisory, the secondand third relays completed by the subsequent deenergization of thesecond relay and the energization of the one supervisory relay.

, 3. A telephone exchange system comprising telephone lines, a linkcircuit connecting the lines, a supervisory and a cooperating localcircuit relay for each end of the link circuit, a signaling device undercontrol of each supervisory relay, a switching device for the linkcircuit, an operatingcircuit for the localcircuit relays establishedupon the actuation of the switching device, interrupter mechanism and acircuit for each signaling device and the interrupter mechanismcontaining contacts of both local circuit relays and its controllingsupervisory relay. 1

4. A telephone exchange system comprising telephone lines, a linkcircuit connecting the lines, a supervisory and, a cooperating localcircuit relay for each end of the link circuit, a signaling device undercontrol of each supervisory relay, a listening key, an operating circuitfor the local' circuit relays established upon the actuation of thelistening key, an independent locking cir-' cuit for each local circuitrclay'controllcd by each supervisory relay, interrupter mechanism and acircuit for each signaling device and the interrupter mechanismincluding contacts of both local circuit relays and its controllingsupervisory relay.

In witness whereof I hereunto subscribe my7name this 16th day ofFebruary, A. D. 191

FREDERICK V. YOUNG.

cepiesof' tliis patent may be obtained for five cents each, byaddressing the Commissioner of Patents, I v Washington, D. G.

